over ten thousand men Crown army. At the disastrous for the Poles Battle of Batoh most of them, including Kalinowski, were killed. The marriage did take place, but the Moldavian boyars conspired against the Hospodar. Tymofiy, defending his father-in-law, died at the Polish-Transylvanian siege of Suceava. The main Polish forces led by John Casimir became stuck at a camp near Zhvanets. John Casimir negotiated with the Tatar Khan İslâm Giray again and in December 1653 accepted in the Treaty of Zhvanets the old Treaty of Zboriv's conditions. The Tatars, concerned with the preservation of the regional balance of power, over all may have saved the Commonwealth, by deciding not to support the Cossacks at crucial junctures. While for the moment they reaped the benefits of their position and actions (the King agreed not to resist the next Tatar slave-taking raids into Poland), for the Poles the Berestechko victory was by that time wasted. The Commonwealth and Cossack combatants were unable to arrive at a military solution, the Crimean and Ottoman alliances had not been reliable for Bohdan Khmelnytsky, and Ukraine was devastated by five years of warfare. Enslavement of Ukrainians by the Tatar "allies", plagues and periods of hunger complemented the destruction and depopulation reached 40% in some regions of the country. The losses caused damage to the cohesiveness of the Cossack army and led to greater pro-Moscow orientation and dependence on the northeastern neighbor. The Cossack hetman turned to his prior concepts of increasing cooperation with Russia (talks with the Tsardom took place already in 1651, but the deal was not consummated at that time because of the Berestechko defeat), the country of more distant common historic tradition, but close linguistic, religious and East Slavic cultural ties with Ukraine. The Cossack leaders expected on the one hand Russia's help in eliminating what was left of the Commonwealth's nobility rule in Ukraine, and broad autonomy for the Cossack state on the other. The Polish reverses in the region convinced Tsar Alexis to abandon his policy of non-involvement and move against the Commonwealth. A Russian mission arrived in Pereiaslav in January 1654 and the Cossack council deliberating there accepted (not without grave misgivings and futile attempts to negotiate concessions) the supremacy of the Tsar. The Cossacks were offered an elected hetman post, a sixty thousand registry and possession of landed estates. Khmelnytsky and his entire Zaporizhian army pledged being faithful followers